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    <title>armac</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>armac</b> -  Scilab description of an armax process</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[ar]=armac(a,b,d,ny,nu,sig)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>a=[Id,a1,..,a_r]  </b>
        </tt>: is a matrix of size (ny,r*ny)</li>
      <li>
        <tt>
          <b>b=[b0,.....,b_s]  </b>
        </tt>: is a matrix of size (ny,(s+1)*nu)</li>
      <li>
        <tt>
          <b>d=[Id,d1,..,d_p]  </b>
        </tt>: is a matrix of size (ny,p*ny);</li>
      <li>
        <tt>
          <b>ny</b>
        </tt>: dimension of the output  y</li>
      <li>
        <tt>
          <b>nu</b>
        </tt>: dimension of the output  u</li>
      <li>
        <tt>
          <b>sig</b>
        </tt>: a matrix of size (ny,ny)</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    This function creates a description as a tlist of an  ARMAX process</p>
    <p>
      <tt>
        <b>ar</b>
      </tt> is defined by</p>
    <pre>

ar=tlist(['ar','a','b','d','ny','nu','sig'],a,b,d,ny,nu,sig);
   
    </pre>
    <p>
    and thus the coefficients of <tt>
        <b>ar</b>
      </tt> can be retrieved by e.g.
    <tt>
        <b> ar('a') </b>
      </tt>.</p>
    <h3>
      <font color="blue">Examples</font>
    </h3>
    <pre>

a=[1,-2.851,2.717,-0.865].*.eye(2,2)
b=[0,1,1,1].*.[1;1];
d=[1,0.7,0.2].*.eye(2,2);
sig=eye(2,2);
ar=armac(a,b,d,2,1,sig)
// extract polynomial matrices from ar representation 
[A,B,D]=arma2p(ar);
 
  </pre>
    <h3>
      <font color="blue">See Also</font>
    </h3>
    <p>
      <a href="arma.htm">
        <tt>
          <b>arma</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="armax.htm">
        <tt>
          <b>armax</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="armax1.htm">
        <tt>
          <b>armax1</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="arsimul.htm">
        <tt>
          <b>arsimul</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="arma2p.htm">
        <tt>
          <b>arma2p</b>
        </tt>
      </a>,&nbsp;&nbsp;<a href="../programming/tlist.htm">
        <tt>
          <b>tlist</b>
        </tt>
      </a>,&nbsp;&nbsp;</p>
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